1. Technical Field
The present invention generally relates to testing systems for testing color wheels, and particularly to a testing system for precisely measuring central angles of filter segments of a color wheel, and an angular position of a timing mark on the color wheel.
2. Description of Related Art
Referring to FIGS. 7 and 8, a color wheel 10 of a projector system is shown. The color wheel 10 includes a round color filter 100, a mounting portion 200, a motor 300 and a timing mark 400 adhered to a sidewall of the mounting portion 200. The color filter 100 is composed of three sector-shaped filter segments, i.e. red, green and blue filter segments 102, 104, 106. Because people perceive different colors with different reaction times, central angles of the red, green and blue filter segments 102, 104, 106 are designed to be different from each other. The timing mark 400 is arranged on the sidewall of the mounting portion 200.
In operation of the projector system, the color filter 100 and the timing mark 400 are driven by the motor 300 to rotate together. The central angles of the filter segments 102, 104, 106 and the angular position of the timing mark 400 relative to the filter segments 102, 104, 106 can be detected to help the projector system recognize positions of the filter segments 102, 104, 106. That is, the central angles of the filter segments 102, 104, 106 and the timing mark 400 help the projector system know which color is being shown in a display of the projector system at a given time. Therefore, the central angles of the filter segments 102, 104, 106 and the angular positions of the timing mark 400 are important parameters, which influence an image-forming quality of the projector system. If the central angles of the filter segments 102, 104, 106 and the actual angular position of the timing mark 400 relative to the filter segments 102, 104, 106 deviate seriously from predetermined central angles of the filter segments 102, 104, 106 and a predetermined angular position of the timing mark 400, the image-forming quality of the video will be greatly degraded.